Direct current fastening device and related control methods

Abstract

A direct current fastening device and related control methods. The fastening device is powered by a direct current power source and includes a variety of safety and control features that allow the fastening device to be safety operated without, for example, a mechanical safety linkage or assembly between a trigger and a fastener firing portion (e.g., a nose switch) that prohibits the operation of the fastening device. Rather, the fastening device described herein employs a controller, a variety of switches, and monitoring techniques to ensure the safe and reliable operation of the fastening device. The configuration of the controller, for example, replaces the mechanical linkages and assemblies between the trigger and the fastener firing portion (e.g., a nose switch) that are ubiquitous safety features for such fastening devices.

What is claimed is: 
     
         1 . A fastening device comprising:
 a trigger portion;   a nose portion;   a fastener magazine configured to receive a fastener;   a first switch, an operational state of the first switch being one of an open state and a closed state;   a second switch, an operational state of the second switch being one of an open state and a closed state; and   a controller configured to
 receive a first signal associated with the operational state of the first switch, 
 receive a second signal associated with the operational state of the second switch, and 
 initiate a firing operation for the fastener when the first signal associated with the operational state of the first switch is indicative of the first switch being in the closed state and when the second signal associated with the operational state of the second switch is indicative of the second switch being in the closed state. 
   
     
     
         2 . The fastening device of  claim 1 , further comprising a third switch, an operational state of the third switch being one of an open state and a closed state, and wherein the controller is further configured to receive a third signal associated with the operational state of the third switch. 
     
     
         3 . The fastening device of  claim 2 , wherein the controller is energized when the first signal associated with the operational state of the first switch is indicative of the first switch being in the closed state or when the third signal associated with the operational state of the third switch is indicative of the third switch being in the closed state. 
     
     
         4 . The fastening device of  claim 2 , further comprising a worklight, the worklight configured to be illuminated when the first signal associated with the operational state of the first switch is indicative of the first switch being in the closed state or when the third signal associated with the operational state of the third switch is indicative of the third switch being in the closed state. 
     
     
         5 . The fastening device of  claim 1 , further comprising a rechargeable battery pack removably securable to the fastening device and including a plurality of battery cells. 
     
     
         6 . The fastening device of  claim 5 , wherein the controller is further configured to monitor a voltage of the battery pack, and prevent the initiation of the firing operation for the fastener when the voltage of the battery pack is below a threshold voltage value. 
     
     
         7 . The fastening device of  claim 1 , further comprising a drive switch and a brake switch. 
     
     
         8 . The fastening device of  claim 7 , wherein the controller is further configured to determine if the drive switch has been short circuited or if the brake switch has been short circuited. 
     
     
         9 . The fastening device of  claim 8 , further comprising a thermal fuse. 
     
     
         10 . The fastening device of  claim 9 , wherein the thermal fuse is intentionally blown when one of the drive switch and the brake switch has been short circuited. 
     
     
         11 . The fastening device of  claim 1 , wherein the first switch is associated with the trigger portion of the fastening device and the second switch is associated with the nose portion of the fastening device. 
     
     
         12 . The fastening device of  claim 11 , wherein the fastening device does not include a mechanical safety linkage connecting the trigger portion and the nose portion. 
     
     
         13 . A method of operating a fastening device that includes a controller, the method comprising:
 receiving, at the controller, a first signal associated with an operational state of a first switch, the operational state of the first switch being one of an open state and a closed state;   receiving, at the controller, a second signal associated with an operational state of a second switch, the operational state of the second switch being one of an open state and a closed state;   initiating a firing operation for a fastener when the first signal associated with the operational state of the first switch is indicative of the first switch being in the closed state and when the second signal associated with the operational state of the second switch is indicative of the second switch being in the closed state; and   firing the fastener following the initiation of the firing operation.   
     
     
         14 . The method of  claim 13 , further comprising
 receiving, at the controller, a third signal associated with an operational state of a third switch, the operational state of the third switch being one of an open state and a closed state; and   energizing the controller when the first signal associated with the operational state of the first switch is indicative of the first switch being in the closed state or when the third signal associated with the operational state of the third switch is indicative of the third switch being in the closed state.   
     
     
         15 . The method of  claim 13 , further comprising removably securing a battery pack including a plurality of battery cells to the fastening device. 
     
     
         16 . The method of  claim 15 , further comprising monitoring a voltage of the battery pack, and preventing the initiation of the firing operation when the voltage of the battery pack is below a threshold voltage value. 
     
     
         17 . The method of  claim 13 , further comprising determining if a drive switch of the fastening device has been short circuited or if a brake switch of the fastening device has been short circuited. 
     
     
         18 . The method of  claim 13 , wherein the first switch is associated with a trigger portion of the fastening device and the second switch is associated with a nose portion of the fastening device, and
 wherein the fastening device does not include a mechanical safety linkage connecting the trigger portion of the fastening device and the nose portion of the fastening device.   
     
     
         19 . A fastening device including a trigger portion, a nose portion, and a fastener magazine configured to receive a fastener, the fastening device comprising:
 a first switch, an operational state of the first switch being one of an open state and a closed state;   a second switch, an operational state of the second switch being one of an open state and a closed state; and   a controller configured to
 receive a first signal associated with the operational state of the first switch, 
 receive a second signal associated with the operational state of the second switch, and 
 initiate a fastener firing operation when the first signal associated with the operational state of the first switch is indicative of the first switch being in the closed state and when the second signal associated with the operational state of the second switch is indicative of the second switch being in the closed state. 
   
     
     
         20 . The fastening device of  claim 19 , wherein the controller is configured to operate in one of a first mode of operation and a second mode of operation. 
     
     
         21 . The fastening device of  claim 20 , wherein, in the first mode of operation, the fastener firing operation is initiated when the first signal associated with the operational state of the first switch is received prior to the second signal associated with the operational state of the second switch, the first signal being indicative of the first switch being in the closed state, the second signal being indicative of the second switch being in the closed state, and the second signal being received by the controller within a predetermined time period of the controller receiving the first signal. 
     
     
         22 . The fastening device of  claim 20 , wherein, in the second mode of operation, the fastener firing operation is initiated when the first signal associated with the operational state of the first switch is received prior to the second signal associated with the operational state of the second switch, the first signal being indicative of the first switch being in the closed state, the second signal being indicative of the second switch being in the closed state, and the second signal being received by the controller within a predetermined time period of the controller receiving the first signal, or
 the fastener firing operation is initiated when the second signal associated with the operational state of the second switch is received prior to the first signal associated with the operational state of the first switch, the second signal being indicative of the second switch being in the closed state, the first signal being indicative of the first switch being in the closed state, and the first signal being received by the controller within a predetermined time period of the controller receiving the second signal.   
     
     
         23 . The fastening device of  claim 19 , further comprising a thermal fuse. 
     
     
         24 . The fastening device of  claim 23 , wherein the thermal fuse is intentionally blown when a fault condition of the fastening device is present. 
     
     
         25 . The fastening device of  claim 24 , wherein the fault condition of the fastening device includes the fastening device becoming jammed. 
     
     
         26 . The fastening device of  claim 24 , wherein the fault condition includes one of a drive switch being short circuited and a brake switch being short circuited. 
     
     
         27 . The fastening device of  claim 24 , wherein the fastening device is prevented from operating when the thermal fuse has been blown. 
     
     
         28 . The fastening device of  claim 24 , further comprising a first sensor configured to generate a first sensor signal and a second sensor configured to generate a second sensor signal. 
     
     
         29 . The fastening device of  claim 28 , wherein the fault condition of the fastening device includes the controller determining that the first sensor signal and the second sensor signal were one of not received in a predetermined period of time or not received in a predetermined sequence.